The making of integrated optics

A US initiative is bringing together leading companies with top academics and universities to create a manufacturing infrastructure for the widespread adoption of integrated photonics.

The US sees integrated photonics as a strategic technology and has set up the American Institute for Manufacturing Integrated Photonics - AIM Photonics - to advance the technology and make it available to a wider community of companies. AIM Photonics, with $610 million of public and private funding, is a five-year initiative ending in 2020. AIM’s long-term goal is to be self-sustaining.

Doug Coolbaugh

“Right now the infrastructure is focussed on electronics and CMOS but photonics is going to be the future,” says Doug Coolbaugh, chief operations officer at AIM Photonics. “There is no other way to do it [very high bandwidth] except using light for ultra fast communications.”

Technologies start at universities and in the labs of companies with large R&D budgets. IBM and Intel, for example, have been developing silicon photonics for over a decade and the technology is ready for deployment. However, the intellectual property developed remains with such companies.

“AIM is not only creating the manufacturing infrastructure for integrated photonics but also ideas and intellectual property that can be used by companies for new products,” says Coolbaugh.

All the elements are being addressed so that small to medium businesses and entrepreneurial ventures can use integrated photonics for their products; companies too small to develop the technology themselves. “That will accelerate the silicon photonics ecosystem and allow new products to come out much faster than it would normally take,” says Coolbaugh.

Manufacturing

Silicon photonics luminary, Lionel Kimerling, professor of materials science and engineering at MIT, and an active member of AIM Photonics, views its focus on manufacturing as an important development.

The discipline of manufacturing is something that the chip industry has mastered through designing process integration, selecting materials and all the qualification standards used to meet system requirements, he says, but is less developed in the photonics industry.

AIM is making available a chip fabrication plant to interested companies. SUNY Polytechnic Institute has been working with MIT for the last six years to develop a 300mm-wafer silicon photonics line at its Albany site. The fab offers a multi-project wafer service whereby several designs can be made on a single wafer, allowing costs to be shared among companies.

AIM is not only creating the manufacturing infrastructure for integrated photonics but also ideas and intellectual property that can be used by companies for new products

A design kit is also being developed featuring key building blocks needed to make an integrated photonics circuit. AIM is working with leading semiconductor industry design automation companies Cadence, Synopsys and Mentor Graphics to provide the software tool environment for designers to develop circuits. “This design environment is compatible with the silicon photonics process here in our fab,” says Coolbaugh.

A packaging and prototyping facility located in Rochester, New York is also being set up. “Photonics packaging is relatively new and certain aspects have not been developed that much,” says Coolbaugh.

Another issue is developing skilled engineers and technicians able to design and manufacture integrated photonics circuits. Whereas electronic chip designers typically have a first degree, photonics engineers tend to have a doctorate because of the deep understanding needed. “This is one of the things we find we are lacking significantly,” says Coolbaugh. “There are just not enough skilled people in the industry to fulfil these needs.”

Professor Kimerling says he is spending much of his time putting together educational material to help attract individuals to pursue a career in silicon photonics. Much of the technology is in place, he says, what is required is to make it accessible to people. “I don’t have 40 more years in the industry, but I could influence the next 40 years by creating these instructional materials and career paths, and getting roadmap consensus that can drive the industry,” says Kimerling.

AIM is also working with universities and companies to develop technology and intellectual property alongside the manufacturing centres. Four research areas have been chosen, covering datacom, analogue RF for telecom involving Infinera, sensors and phased arrays. These are areas where AIM sees products emerging in volume in the next five years.

Keren Bergman, whose work focusses on the intersection of photonics and computing systems, mentions how AIM Photonics has already benefited her research group through much closer interactions with companies in the area of datacom. “It has had a big impact on our work,” says Bergman, professor and director at the Lightwave Research Laboratory at Columbia University.

Each year AIM will review and add new research topics. “There are new ideas, new materials and new manufacturing processes that will be developed,” says Coolbaugh. He cites the use of silicon photonics to drive robots as an emerging application area.

Status

AIM expects the entire manufacturing infrastructure to be in place in the next couple of years.

“Right now it is only the photonics design part but we will also be putting in interposers for packaged designs," says Coolbaugh. Interposers are a key technology that allows the co-packaging of chip dice, an approach known as system-in-package or 2.5D packaging.

AIM expects to offer multi-project wafers with interposers and system-in-package by 2017, with the ability to add CMOS dice in 2018. AIM is also developing a test, assembly and packaging facility which it expects to be available by 2018. “Testing is a really critical component of this entire infrastructure,” says Coolbaugh.

The goal is to develop new ways of fast-testing photonics on wafers, while there will be the high-speed testing of circuits at Rochester. “What we design has got to work in the fab, the fab has got to test well and then what we package has to be consistent with what we deliver to the packaging house,” says Coolbaugh. “The entire flow has to integrate exactly.”

A start-up or small company wanting to make a product can already use the design kit - which continues to evolve - and benefit from AIM’s multi-project wafer service. Then there will be the Rochester packaging and prototyping site. Low volumes can be made at the Albany fab while AIM will pass higher-volume manufacturing requests to leading chip fabrication players such as GlobalFoundries.

Companies can take a concept, develop their own product and have their own business. “We provide the entire chain for the infrastructure,“ says Coolbaugh. ”Right now, this is only available to large companies.”

If all goes to plan, what impact will AIM have on integrated optics and silicon photonics in particular? “It will be a worldwide impact,” says Coolbaugh. “Just because we want to create the infrastructure in the US doesn’t mean we are limiting our customers to the US.”

Further information

For AIM Photonics presentations, click here 

The text is based on an article that first appeared in Optical Connections magazine